Dr. Golding has developed mutant T-cell lines which differ from wild type in the number of CD4 surface receptors and the ability for form syncytia after infection by HIV-1. The ability of mutant t-cell lines to replicate HIV was monitored by reverse transcriptase (RT) activity. Several cell lines exhibited altered kinetics of viral replication. Some mutant cell lines were shown to express only 5-10% CD4 receptors but parental RT activity and syncytia. Other mutants were shown by RT activity to produce, but not readily release infectious virion. Some of the data was published in J. Immun.144:2131-2139,1990.